Static Electricity 2000 Edition

9.1.7.2 Charge Generation.
Static electric charges can be
generated during filling and emptying of FIBCs and can accu-
mulate on both the contents and the fabric of the FIBC. If the
accumulated charge is strong enough and is released in the
presence of an ignitible atmosphere, ignition can occur.
9.1.7.3 Nonconductive FIBCs.
FIBCs constructed of noncon-
ductive materials (e.g., polypropylene fabric with polyester
stitching) have no special features incorporated in their
design to minimize static electric charging. These nonconduc-
tive FIBCs can be used for materials that do not form ignitible
atmospheres in normal handling operations. Experience has
shown that granular materials that do form dust clouds during
handling can also be safely handled in these FIBCs, provided
the dust clouds generated cannot be easily ignited by a static
electric discharge. In other words, the material should have an
MIE for a dust cloud that is greater than 100 mJ. These FIBCs
should not be used for granular materials that have a mini-
mum ignition energy less than 100 mJ and should never be
used in areas where a flammable gas or vapor is present.
9.1.7.4 Conductive FIBCs.
9.1.7.4.1
FIBCs constructed of conductive fabric can be
treated the same as conductive IBCs, as specified in 9.1.5. If
conductive FIBCs are used with a liner, the recommendations
of 9.1.5.3 also apply. It is essential that these FIBCs be
grounded during all operations.
9.1.7.4.2
FIBCs constructed of nonconductive fabric and con-
taining woven, grounded, conductive filaments can be consid-
ered to be conductive. One type has conductive filaments that
are spaced less than 20 mm apart, each of which is connected
at least once to its neighbor, preferably at one end, and are
intended to be grounded. Another type has conductive fila-
ments or threads that form an interconnecting grid of not
more than 50 mm mesh size and are also intended to be
grounded. The recommendations for conductive IBCs given

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SPECIFIC APPLICATIONS
77
–31
2000 Edition
in 9.1.5 also apply to these FIBCs. A grounding tab that is elec-
trically connected to the conductive threads is provided and is
intended to be connected to a ground point when the FIBC is
filled or emptied.